This invention relates to a high frequency crosstalk eliminating circuit which eliminates high frequency crosstalk in a device which reproduces a record carrier such as, for instance, from a video disc in which a frequency-modulated video signal is recorded along tracks.
In a video disc in which a frequency-modulated video signal is recorded along tracks and the video signal is read while the video disc is turned at a constant linear velocity, there are no synchronizing signals recorded in a predetermined angular region subtended by the center of rotation. Therefore, when a video signal is recorded at a predetermined position on a track, there is sometimes a synchronizing signal recorded at a position, corresponding to the aforementioned predetermined position, of a track adjacent thereto, as shown in FIG. 1. In such a case, the recorded data being reproduced on a track 1 may be as indicated by the curve 3 in FIG. 1, while the recorded data on a track 2 adjacent thereto may be as indicated by the curve 4 in FIG. 1, with the synchronizing signals of the former being shifted relative to those of the latter. When a video disc according to this recording system is played back with an RF signal cross talk on the order of -32 to -35 dB, a part B of the signal on the reproducing track 1, which corresponds to the blanking period A of the adjacent track, will result in an irregular picture; that is, the synchronizing signal from the blanking period A will appear in the reproduced signal B in the form of a belt having a certain width in the picture as indicated at C or D in FIG. 2, thus causing a so-called "window wiper interference" wherein the belt is moved vertically or horizontally. Because of this interference, the picture appears unsatisfactory. In FIG. 2, reference character P designates a portion of the picture which changes complicatedly e.g. a portion which includes a complicated color pattern.